Chapter 0.8, Problem 19E

To determine

To calculate: The area of the polygon

Answer to Problem 19E

The area of the polygon is $\text{20 square units}$ .

Explanation of Solution

Formula used:

Area of a polygon on square sheet is the number of full squares, half squares and almost-full squares that covers the surface of the figure.

Almost-full squares are counted as full squares.

Two half squares are equal to one whole square.

The squares which are less than half full are not counted.

Calculation:

Recall that area of a polygon on square sheet is the number of full squares, half squares and almost-full squares that covers the surface of the figure.

To evaluate the area of the polygon, we need to count the number of full squares, half squares and almost-full squares.

Number of full squares $=12$ .

Number of almost full squares $=7$ .

Recall almost-full squares are counted as full squares.

Number of half squares $=2$ .

And we know that two half squares are counted as one whole square.

So, $\frac{2}{2}=1$

There are 6 squares which are less than half full, so, they won’t be counted.

To estimate the area of the polygon, add the above number of squares.

  $\begin{array}{c}\text{A=12+7+1}\\ \text{=20}\end{array}$

Thus, the area of the polygon is $20$ square units.